Chemistry Ph.D. viva-voce of Mr. Ashish Kumar Chalana on 1st October 2019 | Shiv Nadar University
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Chemistry Ph.D. viva-voce of Mr. Ashish Kumar Chalana on 1st October 2019

The Ph.D. viva-voce examination of Mr. Ashish Kumar Chalana, Department of Chemistry, School of Natural Sciences, is scheduled as follows: 

Date:    Tuesday, 1 October 2019 

Time:    9.30 AM to 10.30 AM

Venue:  D330, SNU


  • Research Advisor: Dr. Gouriprasanna Roy, Department of Chemistry, SNU
  • Chair of Oral Examination Committee: Dr. Bani Kanta Sarma, Department of Chemistry, SNU
  • Internal Examiner: Dr. Basab Bijayi Dhar, Department of Chemistry, SNU
  • External Examiner: Prof. Sasankasekhar Mohanta, Department of Chemistry, University of Calcutta

Thesis title:   “Structural and Physical Properties of Chalcogen-based Copper Complexes and their Significance in Copper-Related Disorders”


Abstract: Heavy metals are considered as an environment pollutant due their toxic effect in human, animals and plants. Few nonessential heavy metals viz. arsenic (As), Cadmium (Cd), Lead (Pb), Mercury (Hg) are cumulative poison. Whereas essential metals also can be toxic if it is taken into higher concentration. For example, copper can accumulate in certain tissues and cells, such as hepatocytes, can cause liver injury. It is well known that copper can equally detrimental as it produces hydroxyl radical (OH) from H2O2 via Fenton-type reactions, and thereby causes oxidative damage to proteins, lipids, and nucleic acids. Copper overload have been implicated in the progression of Wilson’s disease (WD) and other neurodegenerative disorders including Alzheimer’s and Parkinson’s diseases. Medical therapy in WD involves lifelong treatment with Cu chelators (penicillamine, trientine) that bind Cu directly in blood and tissues and facilitate its excretion. However, chelation therapy is not always efficient for symptomatic neurological patients and has harmful side effects and, thus, efforts were made to discover tissue specific chelators.

This thesis describe the discovery of new set of benzimidazole-based novel thione/selone molecules which has remarkable ability to reduce the bioavailability of intracellular Cu concentration in the case of excess copper related disorders. In the two chapters, we have describe the synthesis of benzimidazole-based [S1]/[Se1] or [S2]/[Se2]-donor thione/selone and also have studied their coordination behaviour with Cu(I) or Cu(II). Another chapter describe the discovery of new set of benzimidazole-based novel selone which has remarkable ability to reduce the bioavailability of intracellular Cu concentration by removing Cu from glutathione, a major cytosolic Cu-binding ligand, and thereafter converts it into copper selenide nanozyme that exhibits remarkable glutathione peroxidase (GPx)-like activity with an excellent cytoprotective effect against oxidative stress in hepatocyte. Since copper selenide have diverse applications, so in one of the chapter, we have shown that copper selenide nanoparticles can be further utilized to cleavage toxic Hg-C bond of various methyl mercury species. 



List of Publications (Included in thesis):

Chalana, A., Karri, R., Das, R., Kumar, B., Rai, R. K., Saxena, H., Gupta, A., Banerjee, M., Jha, K. K., Roy, G*. Copper-driven Deselenization: A Strategy for Selective Conversion of Copper Ion into Nanozyme and Its Implication for Copper-Related Disorders. ACS Appl. Mater. Interface 2019, 11, 4766-4776.

Chalana, A., Karri, R., Mandal. S., Pathak. B., Roy, G*. Chemical Degradation of Mercury Alkyls Mediated by Copper Selenide Nanosheets. (Chem. Asian J., In Press).

Chalana, A., Rai, R. K., Kumar. B., Roy, G*. Exploring the Coordination Chemistry of Benzimidazole-based Thiones with Copper and Evaluation of Their Ability to Scavange Reactive Oxygen Species. (Manuscript Submitted)



Roy. G*., Banerjee. M., Karri. R., Chalana. A., Das. R. Derivatives of Imidazole and Benzimidzole, Method of Preparation and Use Thereof. (International Publication Number WO 2017/168451 A1)

Book Chapter:

Banerjee, M., Karri, R., Muthuvel, K., Chalana, A., Roy, G. “Detoxification of Mercury: Bioremediation to Chemical Degradation, in “Metal-Microbe interactions and bioremediation: Principle and applications for toxic metals.” Published by Taylor & Francis (CRC Press), Ed: Das, S. and Dash, H. R.; 2016.


List of Publications (Not included in teh thesis):

Karri, R., Chalana, A, Kumar, B, Jayadev. M., Roy, G*.  Exploiting the κ2-Fashion Coordination of [Se2]-donor Ligand L3Se for Facile Hg—C Bond Cleavage of Mercury Alkyls and Excellent Cytoprotection Against Methylmercury-Induced Toxicity. Chem. Eur. J. 2019, 25, 1–11. (

Rai, R. K., Chalana, A., Karri, R., Das, R., Kumar, B., Roy, G*. Role of Hydrogen Bonding in Protecting Copper(I)-mediated Oxidative Damage of Biomolecules by Thiones. Inorg. Chem. 2019, 58, 6628–6638.

Karri, R., Chalana, A., Das, R., Rai, R, K., Roy, G* Cytoprotective effects of imidazole-based [S1] and [S2]-donor ligands against mercury toxicity: a bioinorganic approach. Metallomics, 2019, 11, 213-225.

Karri, R., Banerjee, M., Chalana, A, Jha, K. K.; Roy, G*. Activation of the Hg–C Bond of Methylmercury by [S2]-Donor Ligands" Inorg. Chem2017, 56, 12102–12115.

Banerjee, M., Karri, R., Chalana. A., Das, R., Rai, R. K., Rawat, K. S., Pathak, B., Roy, G.* Protection of Endogenous Thiols against Methylmercury by Benzimidazole-based Thione via Unusual Ligand Exchange Reactions". Chem. Eur. J. 2017, 23, 5696–5707.

Event Date: 
Tuesday, October 1, 2019 -
Tuesday 01, Oct 2019
09:30 AM - 10:30 AM